we have a 4 stop with 3 stage telescopic jacks. When you leave a floor or level into a floor you get a lot of vibration. If you manual lower the unit it will shutter at a certin speed also. We have repacked,replaced regulator valves, and bearind surfaces. Replumed jacks and added shims to level the jacks out. We have added pro-vantage to the oil and piston surfaces. No luck at all. The unit runs hot but not all that bad. And resinking has no effect on this problem. Anyone seen this before. Thanks in advance Dan

"When you leave a floor or level into a floor you get a lot of vibration."
Is this effect happening in both the up, and down directions?

Have you tried speeding up, or slowing down the accel and/or decel, to avoid those slip-stop harmonics?

Is there any isolation between the top of the pistons and the sling, where the pistons bolt up? Maybe you could insert some rubber isolation there.

Do you have an extended crosshead on top of the car, where the pistons bolt up? Sometimes I heard they can flex, might need stiffening.

What did you repack it with? OE? Texacone makes a super slick graphite packing, (well, I think they still do) which reduces friction. Autopack might help, too.

Does the temperature of the oil make a difference? Like, is it worse when it heats up? An oil cooler, (or even a heater! but probably not in your case!) might have some benefit.

I'm sure that you've tried this, but if not, when performing a manual resynch, remove the buffer springs or even unbolt the buffer stands, lay 'em on the pit floor and try the resynch. I've seen pit depth issues, buffer stand height problems and other variables that don't allow for a total, open both check valves resynch.

I've had many issuses w/ these units. A couple things to try, make sure when resyncing that the car is fully compressed on the springs before the low pressure switch opens. The low pressure switch will disable all further down movement and thus not allow a full resync. Also increase your down leveling speed a touch w/o comprimising the down ride quality. If you have access to a service tool increase the resync time so the car has plenty of time to even out.

dan what type of telescopic ram is it? the automatic type with cross bars connected to the rails with no other mechanical connections or the schindler type with sprockets and chains connecting each section with the top section connected to the car with the cross member connected to the rails? i know we have had to replace the sprocket bearings quite alot. also i have split them before but would imagine there are guides/seals on the outside(internally)of each ram and maybe they are worm out or its the actual caissons the are worn.

the otis telescopic jacks do the same thing. we increase leveling speed and pump a quart of cat oil into the jack sections with a high pressure pump. the smaller jacks are isolated from the others and the tank on the otis system so you have to pump it directly in. a piece of unistrut to stiffen the car frame helps also

Is there any rubber/neoprene isolation between the piston and car sling? As much as it doesn't seem like it would do anything...it does.

Must be an amee telescoping jack. Use slip it on the guides.

We picked up a car with the same problem , you could hear it any where in the building when it leveled into the floor and have to agree with green pants 2quarts of cat additive did the trick. I put it into the tank but it takes weeks or a month to work.

Thanks for all the suggestions. Yes we have added rubber isolation We repacked with OEM I normally only buy the supream green from Texacone when I can. We have even unbolted the pistons from the cross head and lowered them all the way. Pistons are direct connect no chains or cables. Adding the pro-vantage (same as cat oil except for the price) We have added to the tank and are having our machine shop make a custom fitting to go from our high pressure pump to the metric bleeder hole. I hold out the most hope that this will cure the problem but wanted to hear you guys opinions.

Do you have an air charged muffler that is out of air and is vibrating due to the empty bladder inside the muffler? Just a thought...

the problem comes from the difference in friction from side to side. you can have the same problem on a single jack holeless if the packings are different side to side. the cat oil is the best solution. a long transition/short leveling, 18-20 fpm leveling speed and if it has oil warming keep the oil hot. then tell the customer they should have bought a traction car. we wish the 3 stage jacks were roped hydros, that how much work we put into these things sometimes.

Steve we have the old style muffler. They will be injecting the cat oil when I am on vacation over the week of the 4th. I will report the out come on my return.